Nautilus shells and ammonite. 1752 engraving of the shell of a nautilus (Nautilus sp. Fig. 1 & 2) and that of an ammonite (Fig. 3),an extinct relative. When cut open,the shell of a nautilus is seen to consist of a spiral of air-filled chambers. The animal lives in the outermost chamber,building successively larger additions through its life. A tube called a siphuncle links the chambers and keeps them filled with gas,which gives the animal buoyancy in its marine habitat. There are only six living species of Nautilus,descended from a large group that originated in the early Palaeozoic Era | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Bernard, George |
Bildgröße: | 3069 px × 4605 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |